The majority of industrially synthesized chemical compounds are prepared from a limited set of precursors, whose ultimate sources are primarily fossil fuels. As these reserves diminish, it would be beneficial to use a renewable resource, such as carbon dioxide, which is a non-toxic, abundant, and economical C1 synthetic unit. The coupling of carbon dioxide with other unsaturated molecules holds tremendous promise for the direct preparation of molecules currently prepared by traditional methods not involving CO2.
One could envision the direct preparation of acrylates and carboxylic acids through this method, when carbon dioxide is coupled with olefins. Currently, acrylic acid is produced by a two-stage oxidation of propylene. The production of acrylic acid directly from carbon dioxide and ethylene would represent a significant improvement due to the greater availability of ethylene and carbon dioxide versus propylene, the use of a renewable material (CO2) in the synthesis, and the replacement of the two-step oxygenation process currently being practiced.
Therefore, what is needed are improved methods for preparing acrylic acid and other α,β-unsaturated carboxylic acids, including catalytic methods.